A COMPARATIVE STUDY OF THE FOLIAR ANATOMY OF LYCOPODIUM SPECIES

A comparative study of the leaves of 31 species of Lycopodium was made. The pattern of tracheids varies with the species. Usually they exhibit annular, helical, reticulate, modified or transition forms; none of the species have advanced phylogenetically beyond the scalariform tracheid stage. Mucilage canals have been found in four species. Tracheids are enclosed by a few to several layers of oblique ended, elongated parenchyma cells in most species, but an endodermis is absent. Vascular bundles are encircled by fiber cells in three species. The mesophyll of most species consists of identically shaped cells, although palisade-like tissue has been observed in a few species. The epidermal cells vary from elongated to isodiametric and have either undulated or smooth anticlinal walls, which are deeply pitted in some species. The outer epidermal walls are usually thick and heavily cutinized. Stomates are distributed on both surfaces in 18 species, on the abaxial surface in 11 species, and on the adaxial side in only two species. Most stomates are practically isodiametric in surface view, broader than epidermal cells, usually parallel to the vein, and at the same level as the adjacent epidermal cell. A typical guard cell has a prominent outer ledge and a less developed inner ledge of cutin in most species. Six groupings are suggested, based on similarity of leaf structure and the known chromosome numbers.     

ANOMALOUS GROWTH AND VEGETATIVE ANATOMY OF SIMMONDSIA CHINENSIS

The anatomy of the stem, root, and leaf of Simmondsia chinensis (Link) Schneider was investigated, as well as the mode of tissue formation in the stem. Perivascular tissue is present as part of the primary body; outermost cell layers of this tissue mature as a fibrous sheath. The first short-lived extrafascicular cambium is generated within the remaining parenchymatous perivascular tissue. Successive independent extrafascicular cambia, organized as complete rings or large arcs, arise within peripheral conjunctive parenchyma produced by previous cambia. Extrafascicular cambia produce secondary xylem centripetally and conjunctive tissue bands and strands of secondary phloem centrifugally. Conjunctive tissue initials produce raylike structures of conjunctive tissue; true vascular rays are absent. The phellogen is actually a region of transition where the peripheral conjunctive parenchyma of previous extrafascicular cambia undergoes further cellular subdivision; a true phellogen is lacking. Xylem bands do not represent annual or seasonal growth increments, and secondary growth in Simmondsia is an unequivocal example of the “concentric” anomaly.     

岗柴与刹柴(茅柴)的茎秆与纤维的比较解剖观察

荻(Miscanthus sacchariflorus)属禾本科多年生草本植物,在长江流域以南分布很广。它不仅是草类纤维中主要的造纸原料植物,而且也有防沙固堤,净化污水等作用。目前湖北省主要是采用荻的茎秆作造纸原料。但湖北省的老苇田里,常有与岗柴形     

COMPARATIVE MORPHOLOGY OF THE COCHLOSPERMACEAE. II. ANATOMY OF THE YOUNG VEGETATIVE SHOOT

The generic scope and systematic position of the Cochlospermaceae were evaluated using observations from the anatomy of the stem, node, and leaf. There are few basic differences in vegetative anatomy between Amoreuxia and Cochlospermum. Secretory cells and canals, dilated phloem rays, and banded phloem are unifying features. Mature nodal anatomy is 3-trace, trilacunar, and the leaves of both genera have elongate, unicellular, branched idioblasts in the spongy mesophyll. Bixa has some features in common with Amoreuxia and Cochlospermum but is distinctive in vascularization of the petiole, leaf anatomy, and vestiture. Rhopalocarpus is quite different from the above genera, and its placement in a separate family is justified on anatomical grounds. The Cochlospermaceae, consisting of Amoreuxia and Cochlospermum, seem more closely related to the Sterculiaceae and Tiliaceae than to the Flacourtiaceae, Cistaceae, or Violaceae.     

松嫩平原羊草种群营养繁殖的季节动态及其生物量与密度关系的分析

本文根据野外定位定期观测,分析了羊草[Aneurolepidium chinense(Trin.)Kitag.]种群和羊草个体群营养繁殖的特点。结果表明,在整个生长季,羊草能不断地进行营养繁殖。在移植当年,羊草分蘖株个体群的营养繁殖潜力比实生苗个体群的更大,两个实验个体群的数量均符合于逻辑斯谛曲线增长。生殖生长对羊草的营养繁殖有较大的影响。天然割草场上的羊草种群在生物量达最高时期,种群植株的大小受密度的制约,平均单株重量与密度之间遵循-0.6699 幂的规律性变化。综合分析表明,在松嫩平原天然割草场上,羊草种群依靠营养繁殖更新延续、自我调节,但该种群尚未达到环境所能容纳的最大数量。     

THE VEGETATIVE ANATOMY OF SCHOPFIASTRUM DECUSSATUM FROM THE MIDDLE PENNSYLVANIAN OF THE ILLINOIS BASIN

Schopfiastrum decussatum, a monostelic pteridosperm, has been recovered from Middle Pennsylvanian age coal balls from six localities within the Illinois Basin. Additional features of stem anatomy include the presence of horizontal sclerotic plates in the inner cortex, secretory ducts in the inner and outer cortex, and adventitious roots. The primary xylem is interpreted as bilobed, emitting massive leaf traces in a distichous manner. Five orders of frond members are described, including pinnules. All orders of the frond contain secretory ducts and tissues characteristic of Schopfiastrum stems. The rectangular, bilobed protostele, and method of leaf trace origin indicate that Schopfiastrum is more closely related to certain lower Carboniferous seed ferns than to contemporary Pennsylvanian pteridosperms.     

THE ECOLOGY OF CHONDRUS CRISPUS AT PLYMOUTH,MASSACHUSETTS. I. ONTOGENY,VEGETATIVE ANATOMY,REPRODUCTION, AND LIFE CYCLE

Carpospores and tetraspores germinate and the germlings develop similarly. A prostrate holdfast of regular or irregular outline is formed if the spore makes direct contact with the substrate. If not, rhizoids grow from the few-celled germling unilaterally in no apparent relation to light or gravity, forming a prostrate holdfast if they encounter a solid substrate, and, in any case, eventually an erect shoot of different anatomy. Tetrasporophytes have been grown to reproductive maturity from single spore cultures in the laboratory. The ontogeny of the procarp and subsequent postfertilization events are described from field material. Only a single putative male plant was found when plants bearing procarps were numerous at Plymouth. Evidence from this study and from other reported observations places in doubt the expected role of fertilization in the diphasic, cytological alternation of Chondrus.     

THE ANATOMY OF CALLOCARDIA HUNGERFORDI (BIVALVIA: VENERIDAE) AND THE ORIGIN OF ITS SHELL CAMOUFLAGE

Callocardia hungerfordi (Veneridae: Pitarinae) lives in subtidalmuds (220 to 240m C.D.) and is covered by a dense mat of mudthat, effectively, camouflages the shell. The periostracum is two layered. The inner layer is thick andpleated, the outer thin and perforated. From the outer surfaceof the inner layer develop numerous, delicate (0.5 mm in diameter),calcified, periostracal needles. These penetrate the outer periostracum.Mucus produced from sub-epithelial glands in the inner surfaceof the mantle, slides over the cuticle-covered epithelium ofthe inner and outer surfaces of the inner fold and the innersurface of the middle mantle fold to coat the outer surfaceof the periostracum and its calcified needles. Increased productionat some times produces solidified strands of mucus which bindmud and detrital material into their fabric to create the shellcamouflage. Calcified periostracal needles have been identified in othervenerids, including some members of the Pitarinae, but how theyare secreted and how the covering they attract is producedand, thus, how the whole structure functions, has not been explained. (Received 7 December 1998; accepted 5 February 1999)     

爪哇曲壳藻亚缢变种胞外多聚物提取方法及其化学组成研究

优化了爪哇曲壳藻亚缢变种(Achnanthes javanica var. subconstricta)胞外多聚物提取方法并分析了其化学组成。结果表明, 使用0.3 mol/L的碳酸氢钠提取时间为2.53h可充分提取非水溶性胞外多聚物而不会破碎细胞, 是最优的提取方法。爪哇曲壳藻亚缢变种胞外多聚物多糖占80%以上, 蛋白质占16%19%, 不含脂类。水溶性多糖的单糖组分摩尔比为: 岩藻糖:半乳糖:葡萄糖:甘露糖:木糖:鼠李糖=2.47:2.13:1:0.69:0.57:0.46,而非水溶性多糖的单糖组分摩尔比为: 半乳糖:岩藻糖:木糖:葡萄糖:甘露糖:鼠李糖=3.56:2.73:1.30:1:0.67:0.57。